Preparation method of thermoplastic waterborne polyurethane-polyurea ester foaming body for wearable device carrier

Abstract

The invention discloses a preparation method of a wearable device carrier for a thermoplastic waterborne polyurethane-polyurea ester foaming body, which comprises the following steps of: preparing a polyurethane-polyurea ester primary polymer which is a polymer with a hexamethylene diisocyanate (HDI) and polyethylene glycol (PEG) structure; carrying out crosslinking to synthesize a polyurethane-polyurea ester copolymer; putting the polyurethane-polyurea ester copolymer into a mechanical foaming machine for foaming; coating and drying, wherein a roll-to-roll continuous process is used for coating; and coiling and ripening, and standing at room temperature to obtain the waterborne polyurethane-polyurea ester foaming body.

Description

Technical Field

[0001] The present invention relates to a polyurethane material foam technology, and particularly to a preparation method technology of an aqueous polyurethane-polyurethane foam for a wearable carrier. Background Art

[0002] In recent years, wearable devices have been increasingly developing towards lightweight, long-term comfort, and real-time sensing functions, posing higher requirements for their base materials. Traditional foams often face problems such as high processing temperature, discontinuous production processes, and poor surface bonding strength, which not only reduce the product yield but also limit their combined applications with conductive films or microsensors.

[0003] The buffer and fitting materials required for current wearable devices face multiple technical pain points in practical applications. First, most foams still use an intermittent foaming process, making it difficult to connect to the production line, resulting in low production efficiency and high costs. Second, the structures of traditional foams are mostly open pores, lacking sufficient airtightness and mechanical support, which is not conducive to thermal pressing or long-term fixation. Third, the thickness, density, and pore size of foams are often affected by stirring conditions and drying control, resulting in inconsistent finished product quality and insufficient mechanical strength. In addition, existing solvent-based polyurethane foam materials pose potential risks to the environment and skin, which is not conducive to long-term application.

[0004] Therefore, there is an urgent need for an aqueous foam material and its preparation method that can stably foam, be suitable for continuous processes, have a microporous structure, and good heat-sealing properties to solve the above pain points and achieve mass production feasibility. Summary of the Invention

[0005] In view of this, the present invention provides a preparation method of an aqueous polyurethane-polyurethane foam for a wearable carrier. The aqueous polyurethane-polyurethane foam can be prepared through a continuous roll-to-roll process, improving production efficiency, reducing the risk of environmental damage, enhancing the biocompatibility and skin-friendly properties of users, and at the same time not affecting its excellent characteristics of being plastically processed at a relatively low temperature, and is particularly suitable for the bonding use of sensing films, sensing layers, or conductive layers.

[0006] The present invention provides a preparation method 100 of an aqueous polyurethane-polyurethane foam for a wearable carrier, comprising the following steps: preparing a polyurethane-polyurethane prepolymer 101, wherein the polyurethane-polyurethane prepolymer is a polymer having a structure of hexamethylene diisocyanate (HDI) and polyethylene glycol (PEG); cross-linking and synthesizing a polyurethane-polyurethane copolymer 102; putting the polyurethane-polyurethane copolymer into a mechanical foaming machine for foaming 103; coating and drying 104; and roll-curing 105 to obtain the aqueous polyurethane-polyurethane foam after standing at room temperature.

[0007] Preferably, the polyurethane-polyurethane prepolymer comprises using polybutylene succinate (PBA) with a molecular weight of 500 to 2,000 as a reactant of the prepolymer.

[0008] Preferably, the polyol is polybutylene succinate (PBA) with a molecular weight of 500 to 2,000.

[0009] Preferably, the step of crosslinking to synthesize a polyurethane-polyurethane copolymer comprises adding a crosslinking agent, wherein the addition amount of the crosslinking agent is 1 wt% to 5 wt% of the total composition.

[0010] Preferably, the mechanical foaming machine forms a foam structure by mechanical gas mixing and external gas introduction, and the foaming ratio of the mechanical foaming machine is 300% to 800% of the original volume.

[0011] Preferably, the stirring speed of the mechanical foaming machine is 400 - 1000 rpm.

[0012] Preferably, the tensile strength of the aqueous polyurethane-polyurethane foam is greater than or equal to 11 Mpa, and the elongation at break is greater than 300%.

[0013] Preferably, the pore structure of the aqueous polyurethane-polyurethane foam is a closed microporous structure, and the pore diameter of the pore structure is 10 - 300 μm.

[0014] Preferably, the aqueous polyurethane-polyurethane foam still maintains flexibility and resilience after thermocompression molding.

[0015] Preferably, the preparation method of the aqueous polyurethane-polyurethane foam for a wearable carrier may further comprise a step of thermocompression molding and laminating, and a film with waterproof, breathable, and moisture-permeable properties may be laminated during thermocompression molding according to requirements.

[0016] Preferably, in the preparation method of the aqueous polyurethane-polyurethane foam for a wearable carrier, the step of thermocompression molding and laminating further comprises a step of forming a receiving groove, so that a buried position is formed on the surface or inside of the aqueous polyurethane-polyurethane foam through thermocompression molding for receiving an electronic device, a sensor, or a display.

[0017] Preferably, the aqueous polyurethane-polyurethane foam can maintain resilience after thermocompression molding and is suitable for applications in flexible electronic products or product structures with buffer requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] To make the above and other objects, features, advantages, and embodiments of the present invention more obvious and understandable, the description of the accompanying drawings is as follows:

[0019] Figure 1Flow chart of a preparation method of an aqueous polyurethane-polyurethane foam for a wearable carrier

[0020] Figure 2 Flow chart of another preparation method of an aqueous polyurethane-polyurethane foam for a wearable carrier Detailed implementation manners

[0021] The following will describe several embodiments of the present invention with reference to the drawings. For the sake of clarity, many practical details will be described together in the following description. However, it should be understood that these practical details are not used to limit the present invention. That is to say, in some embodiments of the present invention, these practical details are not necessary. In addition, for the purpose of simplifying the drawings, some conventional structures and components will be shown in a simple schematic manner in the drawings; and repeated components may be represented by the same reference numerals.

[0022] Please refer to Figure 1 , a preparation method 100 of an aqueous polyurethane-polyurethane foam for a wearable carrier, comprising the following steps: preparing a polyurethane-polyurethane prepolymer 101, wherein the polyurethane-polyurethane prepolymer is a polymer having a structure of hexamethylene diisocyanate (HDI) and polyethylene glycol (PEG); crosslinking and synthesizing a polyurethane-polyurethane copolymer 102; putting the polyurethane-polyurethane copolymer into a mechanical foaming machine for foaming 103; coating and drying 104, which is carried out by using a roll-to-roll continuous process coating; and roll maturing 105, so as to obtain the aqueous polyurethane-polyurethane foam after standing at room temperature.

[0023] The step 101 of preparing a polyurethane-polyurethane prepolymer comprises using polybutylene adipate (PBA) with a molecular weight of 500-2000 as a reactant of the prepolymer, and then carrying out the step 102 of crosslinking and synthesizing a polyurethane-polyurethane copolymer.

[0024] Specifically, the polyurethane-polyurethane prepolymer is cited from Patent No. TWI733144B, which is a polymer containing HDI and PEG. After reacting with the polyol at 70 °C for 1 hour, a secondary prepolymer can be obtained. Among them, the polyol is selected from polyester-type or polyether-type polyols such as PBA and polytetramethylene ether glycol (PTMG). Preferably, it is PBA.

[0025] Specifically, in the process of synthesizing the secondary prepolymer, the addition amount of the prepolymer can be 2.2 moles, and the addition amount of PBA-1000 can be 1 mole, but it is not limited thereto.

[0026] Next, first react the secondary prepolymer with 0.7 moles of DMPA and 0.3 moles of 1,4-BD, and dilute with acetone to reduce the overall viscosity to facilitate the reaction.

[0027] Further, at 25 degrees Celsius, after rapid stirring at 1000 - 2000 rpm, add 0.7 moles of a divalent ion neutralizer to form an initial aqueous polyurethane solution. Then, let the initial aqueous polyurethane solution stand at 25 degrees Celsius for 24 hours, and then add a crosslinking agent to obtain the polyurethane-polyurethrane copolymer.

[0028] Specifically, the divalent ion neutralizer can be calcium hydroxide, which can better increase its polymer strength.

[0029] Further, the crosslinking agent can be CDI, and its addition amount can be 1 wt% - 5 wt%. More preferably, the addition amount of CDI can be 3 wt%.

[0030] It is worth mentioning that the molecular weight of PBA can be selected according to the target mechanical properties purpose. Preferably, the molecular weight of PBA can be 500 - 2000, and more preferably, the molecular weight of PBA can be 1000.

[0031] Next, put the polyurethane-polyurethrane copolymer into a mechanical foaming machine for foaming. The parameters of the mechanical foaming machine can be a foaming ratio of 3 - 8 times, a feeding flow rate of 0.3 - 1 L / min, and a stirring speed of 400 - 1000 rpm. After injecting air through a pneumatic pump and high-speed stirring, it can enter a continuous roll-to-roll coater.

[0032] Specifically, the coating and drying step 104 is completed by the continuous roll-to-roll coater. The coating thickness can be 0.3 - 4 mm, the oven temperature in the first zone can be 65 - 100 degrees Celsius, and the oven temperature in the second zone can be 75 - 120 degrees Celsius.

[0033] Finally, through the step 105 of winding and aging, let it stand for 24 - 72 hours and then cut and package.

[0034] Thus, through the above steps, an aqueous polyurethane-polyurethrane foam with excellent mechanical properties and biocompatibility can be obtained through a continuous roll-to-roll process.

[0035] Please refer to Figure 2 , another preparation method 200 of the aqueous polyurethane-polyurethrane copolymer, the steps 201 - 205 of which are the same as those of the preparation method 100 of the aforementioned aqueous polyurethane-polyurethrane copolymer, will not be elaborated here.

[0036] Furthermore, another method 200 for preparing a waterborne polyurethane-polyurethane copolymer includes a hot pressing and laminating step 206, which can be hot pressed according to the designed mold as required, and can be further laminated with a waterproof, breathable and moisture-permeable film, but not limited thereto. If there are other monitoring requirements, circuit printing can also be performed on the surface of the film to monitor the surface.

[0037] Specifically, the hot pressing and laminating step 206 may further include a step of forming a receiving groove, so that a buried position is formed on the surface or inside of the waterborne polyurethane-polyurethane foam through hot pressing, for receiving an electronic device, a sensor or a display.

[0038] Furthermore, the waterborne polyurethane-polyurethane foam can maintain its resilience after hot pressing, and is suitable for being embedded with the above monitoring device and then applied to flexible electronic products or product structures with buffer requirements.

[0039] In summary, the present invention provides a method for preparing a waterborne polyurethane-polyurethane foam for a wearable carrier. The waterborne polyurethane-polyurethane foam can be prepared through a continuous roll-to-roll process, improving production efficiency, and without affecting its excellent characteristics of being plastically processed at a relatively low temperature. The waterborne foam material and manufacturing method with a microporous structure and good heat sealability are particularly suitable for the lamination and use of a sensing film,

[0040] a sensing layer or a conductive layer, so as to solve existing pain points and realize mass production feasibility.

[0041] Although the present invention has been disclosed as above in embodiments, it is not intended to limit the present invention. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to that defined by the appended claims.

Claims

1. A method for preparing an aqueous polyurethane-polyurea ester foam for a wearable carrier, characterized in that: It includes the following steps: Prepare a polyurethane-polyurea prepolymer, wherein the polyurethane-polyurea prepolymer is a polymer having a hexamethylene diisocyanate (HDI) and polyethylene glycol (PEG) structure; Cross-linking to synthesize a polyurethane-polyurea copolymer; The polyurethane-polyurea copolymer is put into a mechanical foaming machine for foaming; Coating and drying, which is a roll-to-roll continuous process coating; The roll is rolled and allowed to stand at room temperature to obtain the waterborne polyurethane-polyurea ester foam.

2. The method for preparing the aqueous polyurethane-polyurea ester foam for wearable carrier according to claim 1, characterized in that: The polyurethane-polyurea prepolymer comprises polysuccinate (PBA) with a molecular weight of 500-2000 as a reactant of the prepolymer.

3. The method for preparing the aqueous polyurethane-polyurea ester foam for wearable carrier according to claim 1, characterized in that: The step of cross-linking to synthesize a polyurethane-polyurea copolymer includes adding a cross-linking agent, wherein the added amount of the cross-linking agent is 1wt% to 5wt% of the total composition.

4. The method for preparing the aqueous polyurethane-polyurea ester foam for wearable carrier according to claim 1, characterized in that: The mechanical foaming machine forms a foam structure by mechanical gas mixing and external gas introduction, and the foaming ratio of the mechanical foaming machine is 300% to 800% of the original volume.

5. The method for preparing the aqueous polyurethane-polyurea ester foam for wearable carrier according to claim 1, characterized in that: The stirring speed of the mechanical bubble making machine is 400-1000rpm.

6. The method for preparing the aqueous polyurethane-polyurea ester foam for wearable carrier according to claim 1, characterized in that: The tensile strength of the waterborne polyurethane-polyurea ester foam is greater than or equal to 11 MPa, and the elongation at break is greater than 300%.

7. The method for preparing the aqueous polyurethane-polyurea ester foam for wearable carrier according to claim 1, characterized in that: The pore structure of the waterborne polyurethane-polyurea ester foam is a closed microporous structure, and the pore diameter of the pore structure is 10-300 μm.

8. The method for preparing the aqueous polyurethane-polyurea ester foam for wearable carrier according to claim 1, characterized in that: The method further comprises a step of heat pressing and laminating, and a film having waterproof, breathable and moisture permeable properties can be heat pressed and laminarized as required.

9. The method for preparing the aqueous polyurethane-polyurea ester foam for wearable carrier according to any one of claims 1 to 8, characterized in that: The steps of hot pressing and laminating further include a step of forming a receiving groove, so that the surface or the inside of the waterborne polyurethane-polyurea ester foam is formed into an embedding position through hot pressing to accommodate electronic devices, sensors or displays.

10. The method for preparing the aqueous polyurethane-polyurea ester foam for wearable carrier according to any one of claims 1 to 9, characterized in that: The waterborne polyurethane-polyurea foam can maintain resilience after hot pressing and is suitable for application in flexible electronic products or product structures with buffering requirements.

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